The subject matter herein generally relates to optical assemblies and, more particularly, to optical assemblies having a light source and one or more lenses.
Many known light sources emit light that, on average, appears to be of a single color. For example, some known light emitting diodes (“LEDs”) emit light that is, on average, of a white color. The color of the emitted light, however, can slightly vary based on the direction that the light emanates from the LEDs. For example, an LED may emit a light that does not have an even distribution of color and appears unattractive or artificial. The direction at which light emanates from the LED may be defined as an azimuth angle and a zenith angle. The zenith angle is the angle between the direction and the optical axis of the light and the azimuth angle is the angle of the direction measured in a plane that is perpendicular to the optical axis of the light.
Known industry standards require that the color of light emitted by a light source be approximately constant across a range of azimuth and/or zenith angles. For example, the Energy Star® program issued Requirements for Solid State Lighting Luminaires, Eligibility Criteria—Version 1.0. These Requirements include minimum criteria for color spatial uniformity, or criteria for the uniformity of the color of light across a range of azimuth and/or zenith angles. Other industry standards and criteria may include additional criteria on the color uniformity of light emitted by a light source. Many known light sources do not satisfy industry standards and criteria relevant to the color of light emitted by the light sources.
Thus, a need exists for improving the color uniformity of light emitted by a light source. For example, a need exists for decreasing the dependence of the color of the light on the direction at which the light emanates from the light source.